In production control it is a common objective to control the work in process (WIP) level in a facility. This is achieved by a number of approaches such as, for example, Just in Time (JIT or Kanban) and Conwip (Constant WIP). Conwip operates by not releasing a production order into the system until a produced item leaves the system. In this way the WIP level is controlled and production on the floor is neither starved of work nor congested with work. In Kanban the same method is applied but at the station level. The methodology caps the WIP level to appropriate values which improves decision making flexibility on the floor. It also tends to reduce shop floor cycle time, and promotes improved quality (since quality issues that arise under suitably low WIP levels tend to amplify production halts and thereby provide the necessary pressure to drive production improvements).
However, Conwip or JIT production methods are not directly applicable in extremely high variety job environments, such as multi-site print production environments, where, in some cases, each job may be unique.